Far-eastern Smartweed is native to Japan, the Russian Far East, China, and Korea. It is a relatively recent addition to the flora of North America with the first specimen being collected near Queens, NY in 1961. It is very similar to our native Persicaria species like the native Curlytop Knotweed and thus goes by unnoticed. According to Robert Naczi, the best way to differentiate between the two species is to look at the tepals, "If I know it's either lapathifolia or extremiorientalis, I find it easiest to examine the tepals. Those of lapathifolia have upside-down anchors. Each main vein splits into two arches that recurve forming a pattern like an inverted anchor. These veins are the single best diagnostic character of Periscaria lapathifolia. Persicaria extremiorientalis, on the other hand, lacks "anchor veins."
There are 14 records in the project database.
| GA | AL | WA | FR | CL | MO | HO | BA | BC | HA | CE | PG | AA | CV | CH | SM | KE | QA | CN | TA | DO | WI | SO | WO |
